How to Measure Ball Screw End Machining Dimensions

Sketch the left and right end structures first

Do not record only one diameter. Separate the fixed side and support side, then record each step by diameter, length, and function from the end face toward the threaded section.

Bearing journal and locking structure matter most

The fixed side usually includes bearing journal, shoulder, lock thread, and lock nut space. If these dimensions are wrong, the support unit may not fit or the bearing cannot be preloaded correctly.

Confirm the coupling end too

The motor coupling end needs diameter, length, keyway, flat, or set-screw position. Many installation problems come from unclear coupling end dimensions, not from the screw body.

Overall length, thread length, and working travel.
Diameter and length of each step.
Bearing journal, lock thread, keyway, and retaining groove.
Support model, coupling size, and photos.

Typical buyer situations

This topic usually appears in distributor stocking, repair replacement, machine retrofit, automation projects, and drawing-based purchasing. If a buyer sends only one model number, the supplier cannot judge the real use, packing risk, or whether machining upgrades are needed.

Details to confirm before quotation

To reduce repeated questions, the RFQ should cover product specification, use case, and delivery expectations together. The following points can be copied into the RFQ form or email.

Purchase purpose: distributor stock, repair replacement, machine project, or sample testing.
Specification: diameter, lead, overall length, thread length, nut type, and quantity.
Machining: cut-to-length, end machining, and whether BK/BF, FK/FF, EK/EF, or other supports must be matched.
Delivery: target quantity, expected lead time, packing, labels, shipping method, and whether shipment photos are required.

Common mistakes

A common mistake is asking only for unit price without application, quantity, or packing details. Another is sending photos without dimensions. This turns quotation into guesswork and can create errors in end machining, nut matching, or long-part shipping.

Next step

If the specification is clear, submit an RFQ directly. If the model or accuracy grade is still uncertain, describe the machine use and old part details so the supplier can recommend a standard part, bar stock, cut-to-length, or end machining route.